Osteoporosis Pathophysiology: Osteoporosis

Presentation of the disease

Osteoporosis is a disease in which the body fails to regenerate enough bone to replace the bone mass that is lost when the body reabsorbs the tissue as part of the natural cycle of bone regeneration. "Bone is living tissue, which is constantly being absorbed and replaced" (Osteoporosis, 2011, Mayo Clinic: Definition). "When you're young, your body makes new bone faster than it breaks down old bone and your bone mass increases. Most people reach their peak bone mass by their early 20s" (Osteoporosis, 2011, Mayo Clinic: Causes). Initially, the disease may not present any symptoms for many years. Some patients do not know they have the condition until they experience an unexpected bone break after a minor trauma or during daily activities. Other symptoms include loss of height, back pain from degeneration of the bone of the vertebrae or stooped posture (Osteoporosis, 2011, Mayo Clinic: Causes).

Etiology

Despite being widely viewed as a disease of old age, osteoporosis can manifest itself at any time. It can also manifest itself in both women and men, regardless of a patients' race or ethnicity. However, since women have less bone mass to begin with, osteoporosis is more commonly diagnosed in women (Osteoporosis, 2011, Mayo Clinic: Definition). The more bone mass someone has by their 20s, the less likely they are to develop osteoporosis.

But while genetics has an undeniable influence upon a person's likelihood of manifesting osteoporosis, a number of environmental factors can raise a person's risk of osteoporosis. Lowered levels of sex hormones, which occurs after menopause in women, means that older women are at an increased risk for osteoporosis although "men experience a gradual reduction in testosterone levels as they age" increasing their risk as well (Osteoporosis,...

The earlier a woman experiences menopause, the greater her risk of manifesting the condition. Women who experience amenorrhea due to anorexia nervosa or bulimia, malnutrition (low levels of calcium and other minerals are associated with osteoporosis); or certain kinds of cancer treatments like chemotherapy have a greater risk. Other, less common risk factors include an overactive thyroid or adrenal gland and weight loss surgeries which interfere with the absorption of vital nutrients (Osteoporosis, 2011, Mayo Clinic: Risk factors).
Taking some medications like steroids increases a patient's risk. "Long-term use of corticosteroid medications, such as prednisone and cortisone, interferes with the bone-rebuilding process" and medications used to treat depression, gastric reflux, and to prevent transplant rejection also increase the likelihood of developing osteoporosis (Osteoporosis, 2011, Mayo Clinic: Risk factors). However, perhaps the most critical risk factors are lifestyle factors. A lack of physical activities that promote rapid bone transfer like weight-bearing exercises and as tobacco and alcohol use are associated with developing osteoporosis.

Clinical manifestations

At its end stages, the symptoms of osteoporosis like a hunched posture or hip or spine fractures after a minor trauma may be extremely obvious. But during the early stages, diagnosis usually requires a bone scan. Clinicians may engage in a form of 'pre-screening,' or identifying patients likely to be at risk because of the other medical conditions they are manifesting, genetic and lifestyle factors, and the medications they are currently taking.

Diagnostic tests

A bone density scan is the most common method of diagnosing osteoporosis. A bone mass density (BMD) score of 2.5 SD or below the average value for premenopausal women…